Ported Coyote Heads Dyno Test - Killer Coyote Cardio

Adding CNC-ported heads to a Coyote powerplant

Richard Holdener

August 3, 2012

If there’s one downside to the new lineup of Mustang engines, it’s the small bore spacing and the attending limit it imposes on available displacement. But rest assured, even at just 5.0 liters, the 5.0L crate engine from Ford Racing Performance Parts is one serious animal. Thanks to the FRPP Controls Pack, the crate engine was a plug-and-play operation, including control over the drive-by-wire throttle and variable cam timing. Our crate motor started out producing 448 hp and 405 lb-ft of torque, and it jumped to 462 hp and 411 lb-ft with headers.

When we first started this Killer Coyote series, we wanted to illustrate as many of the performance components available, so we followed up with a bonanza of bolt-ons, including Zex nitrous, a Kenne Bell supercharger, and we even swapped the stock cams for a set of Stage 2 NSR grinds from Comp Cams (PN 191100). The nitrous upped output to 554 hp, while the Kenne Bell Twin Screw pushed this the Coyote to 704 hp and 549 lb-ft of torque at less than 10 psi.

Given the impressive output, we were thankful for the Aeromotive A1000 fuel system employed on the engine dyno. The cams increased horsepower substantially, especially when combined with a new air intake from JLT. Equipped with cams and JLT air intake, the little 5.0L produced 515 hp and 450 lb-ft of torque.

It is understandable to expect big horsepower numbers from a four-valve motor, but what really impressed us was the torque production. Exceeding 100 hp per liter (1.705 hp per cubic inch) is impressive, but this street motor offered BMEP numbers (effectively torque output relative to displacement) of 212, and on pump gas no less!

Put into perspective, most street motors have BMEP numbers in the low-to-mid 170s with very powerful (high-compression) combinations touching 200. Exceeding 200 often takes a dedicated race motor with 13.0:1-plus compression, a solid-roller cam, and dry-sump oiling system. This Coyote offered the best BMEP number we’ve ever tested on a street motor on pump gas.

Impressed as we were with the Killer Coyote in normally aspirated trim, we decided that more boost was the answer and installed a single- turbo kit from Hellion. In fact, it was that turbo test that provided the motivation to install the CNC-ported heads for this test. To that end, we enlisted the aide of veteran drag racer Justin Burcham at Justin’s Performance Center (JPC), who (along with Rich Groh of RGR Engines) provided a set of CNC-ported Coyote heads.

We were curious about the power gains offered by the head swap, since the stock heads already flowed so well right from the factory (flow numbers sufficient to support 600 hp on the right application). Since our mild Coyote was making nowhere near that much power, we couldn’t help but question the logic of extra cardio for our Coyote. Our concerns were quickly put to rest.

The Stage 1 heads supplied by JPC and RGR featured full CNC porting. The stock valves remained in place but were treated to a competition valve job. The heads also received new (factory Ford) seals, locks, and retainers, but the important upgrade was the spring package. Given our past experience with the valve float issue, we were excited about the increase in valvespring pressure.

Using the stock retainers and keepers, the new springs offered 80 pounds of seat pressure and 200 pounds of open pressure. These spring rates may not seem like much compared to race hardware for a traditional small-block, but remember, the Coyote sported four small valves compared to a pair of larger (and heavier) valves in the conventional small block. It’s the small, lightweight valves that allowed the engine to utilize such (relatively) light spring pressure. Though we did not flowbench test the heads, JPC claims that the porting improved the flow rate of the Coyote heads from just under 300 cfm to over 330 cfm (roughly 10 percent).

Photo Gallery

Some enthusiasts may be intimidated by the DOHC layout that includes variable cam timing, but the reality is that swapping the heads wasn’t terribly difficult. The only real trick was making sure the cams were lined up properly.

The chain and sprockets all feature timing marks, and since we had previously swapped out the cams, this was still fresh in our minds. Off came the cam covers, damper, and front cover to allow access to the cam sprockets and timing chains. We took photos just to be sure, but we lined up the cams and crank at TDC—then we removed the tensioners, guides and cam sprockets. Next came the Comp cams from the stock heads, followed by the lifter/rocker assemblies (they were attached by a clip), and finally the stock head bolts.

The stock heads were removed and replaced by the CNC heads from JPC/RGR using the stock head gaskets. Since we planned on more boost in the future, we took the opportunity to upgrade the hardware to ARP head studs. ARP also supplied a set of main studs and damper bolt, but the main studs will have to wait until we upgrade the bottom end. With CNC-ported heads in place, we installed the Comp cams, lined up and installed the timing chains, and buttoned up the front and valve covers.

Once the stock intake manifold and throttle body were in place, we connected the JLT air intake and were ready to go. Once again, super-tuner Ken Christley from Kenne Bell was on hand to dial in the factory ECU using SCT software. After a brief warm up, we were rewarded with a significant jump in power.

Equipped with the stock heads, this combination produced 515 hp and 450 lb-ft of torque. After the installation of the CNC-ported heads from JPC, the peak numbers jumped to 545 hp and 475 lb-ft of torque. Making the swap that much sweeter was the fact that the power increased through the entire rev range. More power is good but more power everywhere is even better.

Though a head swap would be enough for most enthusiasts, we decided the Coyote needed even more power. Once again, the power came from Ford Racing in the form of a Boss intake manifold and matching throttle body. Adding the Boss intake upped the power output from 545 hp and 475 lb-ft to 571 hp and 449 lb-ft. Designed for high rpm, the Boss lost power compared to the stock intake up to 6,500 rpm, but where the stock intake fell off, the power curve offered by the Boss kept climbing, right up to 7,500 rpm.

The list of mods to our normally aspirated Coyote now included heads, cams, intake, throttle body, headers, air intake, and programming. Having exhausted the basic bolt-ons, you might think we would be done with the Coyote, but you’d be wrong.

Despite the fact that we have increased the power output of the Coyote by 123 hp and 45 lb-ft (from 448 hp and 405 lb-ft to 471 hp and 449 lb-ft), we want even more before giving the blower and turbo systems one more chance. We are inching ever so close to the 600hp mark in normally aspirated trim, so we have decided to take one last shot and get the 5.0L to produce an honest 600 hp.

Look for Stage 3 cams, a revised air intake, and even a custom intake manifold to help reach our goal. After that, we plan on running the Hellion turbo system, then following up with the Kenne Bell supercharger once again.

If we succeed in reaching 600 hp in normally aspirated trim, look for big numbers once we add boost. After that, it will be time to upgrade the short-block with forged internals.

Stick around—this killer Coyote is about to grab that Road Runner and ring his little neck.